I am not familiar with this kit, but I have used the Dos Equis Amber clone kit from Austin homebrew. It turned out very well. It does use a lager yeast. If you are not able to do lagering they give instructions for fermenting at ale temps.
Here is a link to the kit if you want to check it out.

If you're trying to make a beer that closely copies a commercial equivalent to the point that it tastes 'Mexican' instead of 'American' or 'Canadian' or 'European', I'm afraid you'll be disappointed. Most kit beers barely resemble the general style on the label, never mind a particular sub-style.

Light lagers are the most difficult to brew from a kit. They make good beer, don't get me wrong- they just don't hit the bullseye.

1. Heat 2 liters of water to hot, but not boiling (I would heat to boiling)
2. Mix in Coopers Mexican Cerveza Kit, DME, brewing sugar and maltodextrine
3. Cool wort in pot to room temperature. Transfer into fermenter. Aerate well and then top up to five gallons.
4. Pitch yeast when temperature is < 80 degrees F. Ferment 65-70 degrees F.

Actually, it's not as bad as it sounds. That recipe coming from BYO isn't right, at least not what Cooper's is saying now. If you buy the package, it says to use the can of Cooper's Mexican Cerveza mix, beer enhancer 2 (which contains dextrose, maltodextrin and Light Dry Malt) and the yeast that comes with it. Doesn't sound weird to me. It also does not get boiled, as none of the Cooper's cans get/need to be boiled because they are the non-boil kind (already all set in the can). Don't see anything weird here, either. I've tried 3 of the Cooper's kits and they are quite good. Finally found someone on another beer forum who has tried this cerveza kit, and made it just as it directed, and he said it was quite tasty-kinda similiar to Pacifico. Sounds good to me, so I think I'll order it!